Automated assembly apparatus and automated assembly method

ABSTRACT

An automated assembly apparatus includes an assembly robot, which has a plurality of hands of different heights and an XY-axis moving unit movable in a horizontal direction, and a plurality of operation base units which have operation bases and Z-axis moving unit capable of moving the operation bases in a vertical direction. The automated assembly apparatus further includes a control unit which raises in advance, before the assembly robot reaches above the operation bases, the operation bases by the Z-axis moving unit to positions where the operation bases do not interfere with the plurality of hands.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automated assembly apparatus and anautomated assembly method, which use an assembly robot.

2. Description of the Related Art

Hitherto, in an automated assembly apparatus which uses a robot, aZ-axis of the robot gripping an assembly component moves up and down toassemble the assembly component to a component to be assembled.

Automated assembly apparatuses have been required to achieve reducedassembling operation time. Japanese Patent Application Laid-Open No.H5-235598 describes a component mounting apparatus which suctions acomponent by a suction nozzle and moves horizontally with respect to asubstrate to mount the component at a predetermined position on thesubstrate.

The component mounting apparatus described in Japanese PatentApplication Laid-Open No. H5-235598 is capable of reducing the componentmounting time to a certain extent. However, the Z-axis has to be raisedto a height which clears the maximum height of an interfering object onthe movement path when XY-axes move. In addition, when mounting acomponent, the Z-axis has to be lowered by the same height it has beenlifted to clear the interfering object. This has been posing a problemin that the time for mounting a component increases as the height of aninterfering object on the movement path increases.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the problem which cannotbe solved by the foregoing conventional techniques, and therefore toprovide an automated assembly apparatus and an automated assembly methodwhich reduce assembly operation time.

To this end, an automated assembly apparatus in accordance with thepresent invention has an automated assembly apparatus which has anassembly robot having a plurality of hands of different heights andXY-axis moving unit movable in a horizontal direction, and a pluralityof operation base units having operation bases and Z-axis moving unitcapable of moving the operation bases in a vertical direction, theautomated assembly apparatus including:

a control unit which raises the operation bases in advance by the Z-axismoving unit to positions, at which the operation bases do not interferewith the plurality of hands, before the assembly robot reaches above theoperation bases.

Further, to this end, an automated assembly method in accordance withthe present invention is adapted to assemble an assembly component to acomponent to be assembled by using an assembly robot which has aplurality of hands of different heights and XY-axis moving unit movablein a horizontal direction, and a plurality of operation base unitshaving operation bases and Z-axis moving unit capable of moving theoperation bases in a vertical direction, the automated assembly methodincluding:

a first operation step of raising a first hand, which is one of theplurality of hands, and a first operation base, which is one of theplurality of operation bases, so as to perform a job on a component tobe assembled and/or an assembly component; and

a second operation step of raising a second hand among the plurality ofhands and a second operation base, which is an operation base other thanthe first operation base, so as to perform a job on a component to beassembled and/or an assembly component after the first operation step,

wherein the second operation base is raised, during a period between astart of the first operation step and a start of the second operationstep, to a height at which the plurality of hands and the secondoperation base do not interfere with each other.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of an automated assemblyapparatus in accordance with the present invention.

FIG. 2 is a schematic diagram of an automated assembly apparatusaccording to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating the configuration of a controlsystem of the automated assembly apparatus according to the embodimentof the present invention.

FIGS. 4A, 4B, 4C, 4D, 4E, 4F, 4G and 4H are explanatory diagramsillustrating the operation of an assembly robot in the automatedassembly apparatus according to the embodiment of the present invention.

FIG. 5 is a flowchart of the operation of the automated assemblyapparatus according to the embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

In the present description, the phrase “the lowermost portion of a hand”means not only the lowermost portion of a hand itself in the verticaldirection but also the lowermost portion of a component projecting froma hand while the hand is gripping the component. Similarly, the phrase“the uppermost portion of an operation base” means not only theuppermost portion of the operation base itself in the vertical directionbut also the uppermost portion of a component on an operation base whilethe component is being placed on the operation base. Obviously, anoperation base or a hand will imply the phrase “the uppermost portion”or “the lowermost portion” even if the phrases are not explicitly used.

An embodiment of the automated assembly apparatus in accordance with thepresent invention will be described with reference to the accompanyingdrawings. In the drawings, like components will be assigned likereference numerals.

FIG. 1 is a schematic perspective view of an automated assemblyapparatus in accordance with the present invention. An automatedassembly apparatus 1 is comprised of an assembly robot 2, a firstoperation base unit 4, a second operation base unit 5, a third operationbase unit 6, a positioning unit 19 and a screw supply unit 28, each ofwhich is placed on a base 3 and movable in a horizontal plane.

The second operation base unit (supply unit) 5 has an operation base 12b, which is a supply pallet suppliably accommodating at least one ormore assembly components 14. The assembly components 14 are gripped andpicked up from the operation base 12 b by an assembly hand 10, whichwill be discussed hereinafter.

The assembly robot 2 is attached to an X-axis moving unit 11 movablymounted on a guide rail of a Y-axis moving unit 21 provided on asupporting post 39 fixed to the base 3. Further, the assembly hand 10and a transfer (moving) hand 9 are mounted on the guide rail of theY-axis moving unit 21 such that the assembly hand 10 and the transferhand 9 are movable in an X-axis direction. The assembly hand 10 has athrough hole 25b serving as a guiding means, which allows the assemblyhand 10 to be positioned with respect to an operation base 12 c, whichwill be discussed hereinafter. An X-axis and a Y-axis are orthogonal toeach other, and the X-axis and the Y-axis lie in the same plane. Theassembly robot 2 does not have a driving unit in a Z-axis direction.

The first operation base unit 4 is a unit for loading a component 23 tobe assembled onto the automated assembly apparatus 1. As with a thirdoperation base unit 6, which will be discussed hereinafter, the firstoperation base unit 4 is capable of positioning and holding thecomponent 23 to be assembled and is composed of a Z-axis moving unit 13a and an operation base 12 a. Each of the first operation base unit 4and the second operation base unit 5, which are holding means, can bemoved in a vertical direction by the Z-axis moving unit 13 a and aZ-axis moving unit 13 b, which move the operation base units in theZ-axis direction.

An operator or a robot (not illustrated) places the component 23 to beassembled on the operation base 12 a, and the component 23 to beassembled is positioned and held by operating a control panel or thelike (not illustrated). Alternatively, however, the component 23 to beassembled may be carried to the first operation base unit 4 by acarrying means (not illustrated).

The third operation base unit 6 is a unit adapted to position and holdthe component 23 to be assembled in order to assemble the assemblycomponent 14 to the component 23 to be assembled. The third operationbase unit 6 is composed of an X-axis moving unit 11 b, a Z-axis movingunit 13 c, the operation base 12 c, and a work holding means 27 forpositioning and holding the component 23 to be assembled. The thirdoperation base unit 6 further includes a guiding means 25 a and acompliance mechanism (profiling means) 26, which is allowed to freelymove in the X-axis direction, the Y-axis direction and a rotationaldirection.

The compliance mechanism 26 has a locking and unlocking mechanism, whichunlocks to enable the operation base 12 c to move when positioning theoperation base 12 c and the assembly hand 10. The locking and unlockingmechanism remains locked except for the positioning, thereby allowingthe operation base 12 c to be locked. Further, the third operation baseunit 6 may be provided with a first rotating means 18, which makes theoperation base 12 c rotatable as necessary.

The positioning unit 19 provided with an operation base 12 d is adaptedto position the assembly component 14 in advance so as to perform highlyaccurate assembly. The positioning unit 19 is placed on a Z-axis movingunit 13 d. Disposed on the positioning unit 19 is a positioning means20, which engages the assembly component to set the phase of therotational direction and the position in the XY-axis direction of theassembly component 14 with high accuracy.

The second operation base unit 5 is adapted to store and supply theassembly components 14, the operation base 12 b being placed on theZ-axis moving unit 13 b. The second operation base unit 5 mayaccommodate a plurality of types of assembly components. Furtheralternatively, a plurality of types of pallets may be arranged to supplya plurality of types of assembly components.

The screw supply unit 28 is adapted to store and supply screws and isprovided with a Z-axis moving unit 13 e.

FIG. 2 is a schematic diagram illustrating the automated assemblyapparatus according to the embodiment of the present invention. FIG. 2is a schematic diagram for explaining the operation of the automatedassembly apparatus, the diagram illustrating the automated assemblyapparatus observed from the direction of an arrow A in FIG. 1. In FIG.2, for the sake of explanation convenience, a component of theconfiguration illustrated in FIG. 1 is omitted. Further, in order tomake the explanation of the positional relationship in the verticaldirection easier to understand, the plane arrangement of some of theoperation base units illustrated in the diagram has been changed fromthe actual plane arrangement.

The automated assembly apparatus 1 has the assembly robot 2 movable on ahorizontal plane, and the plurality of operation base units, namely, thefirst operation base unit 4, the second operation base unit 5, and thethird operation base unit 6, each of which is disposed on the base 3 andhas the Z-axis moving unit movable in the vertical direction.

The assembly robot 2 has an XY-axis moving unit 7 provided with theX-axis moving unit 11 and the Y-axis moving unit 21. The XY-axis movingunit 7 has a plurality of hands 8 having different heights to perform anassembly operation. The plurality of hands 8 having different heightsare comprised of the transfer hand 9 and the assembly hand 10.

The first operation base unit 4 is adapted to load the components 23 tobe assembled onto the automated assembly apparatus 1, and includes theoperation base 12 a and the Z-axis moving unit 13 a. To supply thecomponent 23 to be assembled to the first operation base unit 4, thecomponent 23 to be assembled is loaded onto the operation base 12 a by aloading means (not illustrated). The component 23 to be assembled mayalternatively be loaded by an operator placing the component 23 to beassembled on the operation base 12 a.

The second operation base unit 5 includes the operation base 12 b, whichsuppliably accommodates at least one or more assembly components 14, andthe Z-axis moving unit 13 b.

The third operation base unit 6 includes the operation base 12 c forassembling the assembly components to the components 23 to be assembled,and the Z-axis moving unit 13 c.

FIG. 3 is a control block diagram of the control unit, which controlsthe automated assembly apparatus 1. A CPU unit 15 controls the operationof the automated assembly apparatus 1 according to a program storedtherein. The CPU unit 15 controls the drive of the XY-axis moving unit7, the Z-axis moving unit 13 a, 13 b, 13 c, 13 d and 13 e, the transferhand 9, and the assembly hand 10 through the intermediary of aninterface 16 and a driving circuit 17. A control panel 30 is operated tostart up the program stored in the CPU unit 15 through the interface 16so as to operate the automated assembly apparatus 1.

Referring now to FIG. 4A to FIG. 4H, the series of operations of theautomated assembly apparatus 1 according to the embodiment of thepresent invention will be specifically described. First, the component23 to be assembled is placed on the operation base 12 a of the firstoperation base unit 4 by the operator or a carrying means (notillustrated). This state is illustrated in FIG. 4A.

After setting the component 23 to be assembled, the control panel 30 isoperated to start up the program stored in the CPU unit 15. Upon thestartup of the program, the XY-axis moving unit 7 and the Z-axis movingunit 13 a are driven by the CPU unit 15 through the driving circuit 17.

When the XY-axis moving unit 7 is driven, the assembly robot 2 starts tohorizontally move to the component-to-be-assembled takeout positionabove the first operation base unit 4. The Z-axis moving unit 13 acauses the first operation base unit 4 to start ascending to thepre-delivery position of the component 23 to be assembled, at which theclearance between the transfer hand 9 and the uppermost portion of thecomponent 23 to be assembled, which has been placed on the operationbase 12 a, reaches a predetermined clearance “c.”

The second operation base unit 5 is started to ascend, by Z-axis movingunit 13 b, to the pre-delivery position of the assembly component 14, atwhich the clearance between the assembly hand 10 and the uppermostportion of the operation base 12 b reaches the predetermined clearance“c.” Further, the third operation base unit 6 is started to ascend, bythe Z-axis moving unit 13 c, to the pre-receiving position of thecomponent 23 to be assembled, at which the clearance between theassembly hand 10 and the uppermost portion of the operation base 12 creaches the predetermined clearance “c.” The state in which theseoperations have been completed is illustrated in FIG. 4B.

Referring now to FIG. 4A to FIG. 4H and the flowchart of FIG. 5, thefollowing will describe the operation performed by the assembly robot 2to take out the component 23 to be assembled from the first operationbase unit 4.

In step S1, the XY-axis moving unit 7 of the assembly robot 2 starts tomove the assembly robot 2 to the takeout position above the firstoperation base unit 4. Meanwhile, before the assembly robot 2 completesits movement to the takeout position above the first operation base, thefirst operation base unit 4 moves in the Z-axis direction to thepre-delivery position (FIG. 4B) in step S8 such that the clearance “c”is present. Additionally, the third operation base unit 6 may be movedin the Z-axis direction to it preassembly position such that theclearance “c” shown in FIG. 4B is present. Of course, the thirdoperation base 6 need not be moved at this time, and in one embodiment,the operation base 6 may be moved in the Z-axis direction to itspre-assembly position upon completion of the robot assembly 2 grippingthe component from the first operation base 4. Once the robot assembly 2has been positioned above the first operation base 4 to the takeoutposition, the assembly robot control program issues an allow to ascendsignal in S2, and the operation base control program receives the ascentpermission signal from the assembly robot 2 in step S9. Thereafter, instep S10, the first operation base unit 4 moves to be assembled deliveryposition at which the component 23 to be assembled can be delivered tothe assembly robot 2.

Subsequently, in step S11, the first operation base unit 4 issues anascent completion signal to the assembly robot 2. Upon receipt of theascent completion signal from the first operation base unit 4 (step S3),the transfer hand 9 grips (holds) the component 23 to be assembled (stepS4), placing the assembly robot 2 in the state illustrated in FIG. 4C.Then, in step S5, the assembly robot 2 issues a descent permissionsignal to the first operation base unit 4. Upon receipt of the descentpermission signal from the assembly robot 2 in step S12, the firstoperation base unit 4 starts to move to a descent position in step S13.

Subsequently, as illustrated in FIG. 4D, a detecting unit (notillustrated) detects that the first operation base unit 4 has passed thepredetermined position, at which the clearance between the operationbase 12 a of the first operation base unit 4 and the lowermost portionof the component 23 to be assembled, which is being gripped by thetransfer hand 9, reaches the clearance “c” (step S14). After thedetection, the first operation base unit 4 issues an avoidancecompletion signal to the assembly robot 2 in step S15. The assemblyrobot 2 receives the avoidance completion signal from the firstoperation base unit 4 in step S6, and starts to move the assembly robot2 to the loading position above the third operation base unit 6 (stepS7).

As illustrated in FIG. 4E, after the assembly robot 2 completes itsmovement to the component 23 to be assembled loading position above thethird operation base unit 6, the assembly robot 2 issues the ascentpermission signal to the third operation base unit 6. Upon receipt ofthe ascent permission signal from the assembly robot 2, the thirdoperation base unit 6 moves to the receiving position of the component23 to be assembled, at which the component 23 to be assembled can bereceived from the assembly robot 2.

Then, the third operation base unit 6 issues the ascent completionsignal to the assembly robot 2. Upon receipt of the ascent completionsignal from the third operation base unit 6, the transfer hand 9releases the component 23 to be assembled to deliver the component 23 tobe assembled to the operation base 12 c, placing the assembly robot 2 inthe state illustrated in FIG. 4F.

Subsequently, the assembly robot 2 issues the descent permission signalto the third operation base unit 6. Upon receipt of the descentpermission signal from the assembly robot 2, the third operation baseunit 6 starts to move to the descent position. As illustrated in FIG.4G, the detecting unit (not illustrated) detects that the thirdoperation base unit 6 has passed the predetermined position, at whichthe clearance between the uppermost portion of the component 23 to beassembled set on the operation base 12 c and the lowermost portion ofthe transfer hand 9 reaches the clearance “c.” After the detection, thethird operation base unit 6 issues the avoidance completion signal tothe assembly robot 2. Upon receipt of the avoidance completion signalfrom the third operation base unit 6, the assembly robot 2 starts tomove to the takeout position of the assembly component 14 above thesecond operation base unit 5. Again, similar to the above descriptionwith regard to the third operation base 6, the second operation base 5may be moved in the Z-axis direction to its pre-assembly position at thesame time as the other bases are moved, or prior to the robot assemblymoving from the operation base 6 to the operation base 4.

As illustrated in FIG. 4H, after the assembly robot 2 completes itsmovement to the takeout position of the assembly component 14 above thesecond operation base unit 5, the assembly robot 2 issues the ascentpermission signal to the second operation base unit 5. Upon receipt ofthe ascent permission signal from the assembly robot 2, the secondoperation base unit 5 moves the assembly component 14 to the deliveryposition of the assembly component 14 at which the assembly component 14can be delivered to the assembly robot 2. Next, the second operationbase unit 5 issues the ascent completion signal to the assembly robot 2.The assembly robot 2 receives the ascent completion signal from thesecond operation base unit 5, and the assembly hand 10 grips theassembly component 14.

Subsequently, the assembly robot 2 issues the descent permission signalto the second operation base unit 5. Upon receipt of the descentpermission signal from the assembly robot 2, the second operation baseunit 5 starts to move to the descent position. Next, the detecting unit(not illustrated) detects that the second operation base unit 5 haspassed the predetermined position, at which the clearance between theoperation base 12 b of the second operation base unit 5 and thelowermost portion of the assembly component 14 gripped by the assemblyhand 10 reaches the predetermined clearance “c.” After the detection,the second operation base unit 5 issues the avoidance completion signalto the assembly robot 2. Upon receipt of the avoidance completion signalfrom the second operation base unit 5, the assembly robot 2 starts tomove to the assembly position of the assembly component 14 above thethird operation base unit 6.

The following will describe the operations performed from the stateillustrated in FIG. 4H until the assembly component 14 is assembled tothe component 23 to be assembled. These operations are similar to thosedescribed above, so that the drawings will be omitted.

After completing the movement to the descent position, the thirdoperation base unit 6 ascends to the pre-assembly position of theassembly component 14, at which the clearance between the operation base12 c and the lowermost portion of the assembly component 14 gripped bythe assembly hand 10 reaches the predetermined clearance “c.” Thisoperation is performed between the start of the movement of the assemblyrobot 2 to the takeout position of the assembly component 14 and thecompletion of the movement thereof to the assembly position of theassembly component 14.

After the assembly robot 2 completes its movement to the assemblyposition of the assembly component 14 above the third operation baseunit 6, the assembly robot 2 issues the ascent permission signal to thethird operation base unit 6. Upon receipt of the ascent permissionsignal from the assembly robot 2, the third operation base unit 6 movesthe assembly component 14 to the assembly component assembly positionwhere the assembly component 14 can be assembled to the component 23 tobe assembled. Then, the third operation base unit 6 issues the ascentcompletion signal to the assembly robot 2. The assembly robot 2 receivesthe ascent completion signal from the third operation base unit 6, andthe assembly hand 10 releases the assembly component 14 to assemble theassembly component 14 to the component 23 to be assembled. Next, theassembly robot 2 issues the descent permission signal to the thirdoperation base unit 6. Upon receipt of the descent permission signalfrom the assembly robot 2, the third operation base unit 6 starts tomove to the descent position. Then, the detecting unit (not illustrated)detects that the third operation base unit 6 has passed thepredetermined position, at which the clearance between the assemblycomponent 14 assembled to the component 23 to be assembled set on theoperation base 12 c and the assembly hand 10 reaches the predeterminedclearance “c.” After the detection, the third operation base unit 6issues the avoidance completion signal to the assembly robot 2. Uponreceipt of the avoidance completion signal from the third operation baseunit 6, the assembly robot 2 starts to move to the takeout position ofthe component 23 to be assembled above the first operation base unit 4.

In step S16, after the first operation base unit completes its movementto the descent position, the component 23 to be assembled is placed onthe operation base 12 a by a carrying means, which is not illustrated(step S17). Thereafter, the first operation base unit 4 moves (ascends)to the pre-delivery position of the component 23 to be assembled, atwhich the clearance between the component 23 to be assembled and thetransfer hand 9 reaches the predetermined clearance “c” (step S18).These operations are performed between the start of the movement of theassembly robot 2 to the loading position of the component 23 to beassembled and the movement back to the takeout position of the component23 to be assembled. It is needless to say that, among the steps, if theresult of any one of the steps S3, S6, S9, S12, S14, S16 and S17 is NO,then the processing repeats the same step or goes back to a precedingstep, as illustrated in the flowchart.

After the third operation base unit 6 completes its movement to thedescent position, the component 23 to be assembled to which the assemblycomponent 14 has been assembled is taken out by the carrying means (notillustrated). After the component 23 to be assembled is taken out, thethird operation base unit 6 ascends to the pre-receiving position of thecomponent 23 to be assembled, at which the clearance between thelowermost portion of the assembly hand 10 and the uppermost portion ofthe operation base 12 c reaches the predetermined clearance “c.” Theseoperations are started at the instant the assembly robot 2 starts tomove to the takeout position of the component 23 to be assembled abovethe first operation base unit 4 holding the component 23 to beassembled. The operations are performed before the assembly robot 2holding the component 23 to be assembled moves back to the loadingposition of the component 23 to be assembled above the third operationbase unit 6 in the state wherein the component 23 to be assembled isbeing held.

After completing the movement to the descent position, the secondoperation base unit 5 ascends to the pre-delivery position of theassembly component 14, at which the clearance between the assembly hand10 and the operation base 12 b reaches the predetermined clearance “c.”This operation is performed between the instant the assembly robot 2starts to move to the assembly position of the assembly component 14above the third operation base unit 6 in the state wherein the assemblycomponent 14 is being held and the instant the assembly robot 2 movesback to the takeout position of the assembly component 14 above thesecond operation base unit 5.

In the foregoing embodiment, the operation bases 12 a, 12 b and 12 c areraised in advance such that the clearance between the operation bases 12a, 12 b and 12 c and the hands 8 (the transfer hand 9 and the assemblyhand 10) will be the clearance “c.” Hence, destination data is retainedin the Z-axis moving unit 13 a, 13 b and 13 c, and the operation isperformed on the basis of the retained destination data.

The foregoing operations are performed by retaining position informationin the CPU unit 15 and by monitoring the current positions of the Z-axismoving unit 13 a, 13 b and 13 c, the current positions being checked bythe values on encoders, which are detecting unit. Alternatively, theascent positions of the operation bases may be determined by comparingthe position information in the CPU unit 15 and the current positions ofthe Z-axis moving unit 13 a, 13 b and 13 c. Further alternatively, thepositions of the operation bases 12 a, 12 b and 12 c may be detected bysensors or image processing so as to determine the ascent positions.

Further, in the foregoing embodiment, the detecting unit, which detectthat the operation bases 12 a, 12 b and 12 c have reached, during theirdescent, the predetermined position at which the clearance between theoperation bases 12 a, 12 b and 12 c and the hands 8 becomes thepredetermined clearance “c,” use the encoders of the Z-axis moving unit13 a, 13 b and 13 c. Alternatively, however, the detecting unit maydetect the positions of the operation bases 12 a, 12 b and 12 c bysensors or image processing.

As described above, the automated assembly apparatus 1 according to thepresent embodiment has the control unit. The control unit raises theoperation bases 12 a, 12 b and 12 c in advance by the Z-axis moving unit13 a, 13 b and 13 c of the operation bases 12 a, 12 b and 12 c to thepositions, at which there will be no interference with the hands 8,before the assembly robot 2 reaches (moves to) a position above theoperation bases 12 a, 12 b and 12 c. Using the control unit reduces theinfluences on the operation time of a process following the operationfor avoiding the interference owing to the difference in height amongthe plurality of hands 8 having different heights and also the operationfor avoiding the interference owing to the difference in height amongthe plurality of operation bases 12 a, 12 b and 12 c. As a result, it ispossible to reduce the operation time of the operation bases 12 a, 12 band 12 c after the assembly robot 2 moves to above the operation bases12 a, 12 b and 12 c, thus permitting shorter time required for theassembly operation.

Further, the present invention includes the assembly robot 2 having theXY-axis moving unit 7, which has the plurality of hands 8 of differentheights and which is movable in the horizontal direction. The presentinvention further provides the automated assembly method forautomatically assembling components by using the plurality of operationbase units 4, 5 and 6, which have the operation bases 12 a, 12 b and 12c and the Z-axis moving unit 13 a, 13 b and 13 c capable of moving theoperation bases 12 a, 12 b and 12 c in the vertical direction. Theautomated assembly method includes raising in advance the operationbases 12 a, 12 b and 12 c by the Z-axis moving unit 13 a, 13 b and 13 cto the positions, at which they will not interfere with the hands 8, andthen moving the assembly robot 2 to above the operation bases 12 a, 12 band 12 c.

Further, the detecting unit is provided to detect that the operationbases 12 a, 12 b and 12 c have reached the predetermined position beforethese operation bases complete the descending operation. The automatedassembly method includes the detection by the detecting unit that theoperation bases 12 a, 12 b and 12 c have reached the predeterminedpositions at which the clearance between the assembly robot 2 and theoperation bases 12 a, 12 b and 12 c becomes the predetermined clearance“c.” The control is performed by the control unit such that the assemblyrobot 2 is moved to above the operation bases 12 a, 12 b and 12 c at theinstant the detecting unit detects the clearance “c.” This controlshortens the standby time of the assembly robot 2, thus making itpossible to reduce the time required for the assembly operation.

Thus, the size of the foregoing predetermined clearance “c” is the samein every case. However, the clearance “c” may be set to differentdimensions according to the relationship between each operation base andeach hand used in an automated assembly apparatus.

The automated assembly apparatus and the automated assembly methodaccording to the embodiment of the present invention described above maybe modified as described below. Although the hands 8 for the assemblingoperation are comprised of two hands, namely, the transfer hand 9 andthe assembly hand 10, the hands 8 may alternatively include anadditional hand adapted to perform another operation. The number of thehands 8 is optional, and two or more hands may be provided.

Further, regarding the operation base units, the three operation baseunits, namely, the first, the second and the third operation base units,have been provided in the embodiment described above. However, thenumber of the operation base units is optional, as with the hands, andthe present invention can be applied to a case where three or moreoperation base units are provided. For example, four operation baseunits, including the positioning unit 19 for positioning illustrated inFIG. 1, may be used.

The present invention provides the advantages described below.

Before an assembly robot reaches the positions above operation bases,the operation bases are raised in advance by Z-axis moving unit of theoperation bases to the positions where the operation bases do notinterfere with the hands. This arrangement reduces the influences on theoperation time of a process following the operation for avoiding theinterference owing to the height difference among a plurality of handshaving different heights and also the operation for avoiding theinterference owing to the differences in height among the plurality ofoperation bases. Hence, it is possible to reduce the operation time ofthe operation bases after the assembly robot moves to above theoperation bases, thus permitting shorter time required for the assemblyoperation.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2015-070770, filed Mar. 31, 2015, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An automated assembly apparatus, comprising: anassembly robot, which has a plurality of hands of different heights andan XY-axis moving unit movable in a horizontal direction; and aplurality of operation base units, each comprised of an operation baseand a Z-axis moving unit capable of moving the operation base in avertical direction; and a control unit which raises at least one of theplurality of operation bases of the operation base units in the verticaldirection by the respective Z-axis moving unit to a position at whichthe operation base does not interfere with at least one of the pluralityof hands to be used for an assembly operation at the respectiveoperation base, before the assembly robot reaches a position in whichthe one of the plurality of hands is positioned above the operationbase.
 2. The automated assembly apparatus according to claim 1, whereinthe assembly robot does not have a driving unit in a Z-axis direction.3. The automated assembly apparatus according to claim 1, furthercomprising: a detecting unit which detects a clearance between lowermostportions of the hands and uppermost portions of the operation bases,wherein the control unit raises the operation bases until the detectingunit detects a predetermined clearance.
 4. The automated assemblyapparatus according to claim 3, wherein the detecting unit is an encoderprovided in the Z-axis moving unit.
 5. The automated assembly apparatusaccording to claim 3, wherein the detecting unit detects the clearanceby a sensor or by image processing.
 6. The automated assembly apparatusaccording to claim 1, wherein at least one of the hands among theplurality of hands and at least one of the operation bases among theplurality of operation bases are provided with members which positionthe hand and the operation base with respect to one another.
 7. Anautomated assembly method for automatically assembling components byusing an assembly robot having a plurality of hands of different heightsand an XY-axis moving unit movable in a horizontal direction, and aplurality of operation base units, each having an operation base and aZ-axis moving unit capable of moving the operation base in a verticaldirection, the automated assembly method comprising: raising at leastone of the plurality of operation bases of the operation base units in avertical direction by the respective Z-axis moving unit to a position atwhich the operation base does not interfere with at least one of theplurality of hands to be used for an assembly operation at therespective operation base, before the assembly robot reaches a positionin which the one of the plurality of hands is positioned above theoperation base; and the assembly robot thereafter reaching above theoperation bases and assembling the components.
 8. The automated assemblymethod according to claim 7, further comprising detection of a clearancebetween lowermost portions of the hands and uppermost portions of theoperation bases.
 9. An automated assembly method for automaticallyassembling an assembly component to a component to be assembled by usingan assembly robot having a plurality of hands of different heights andan XY-axis moving unit movable in a horizontal direction, and aplurality of operation base units, each having an operation base and aZ-axis moving unit capable of moving the operation base in a verticaldirection, the automated assembly method comprising: a first operationstep of performing a first job on a component to be assembled using afirst hand, which is one of the plurality of hands, and a firstoperation base, which is one of the plurality of operation bases; and asecond operation step of performing a second job on the component to beassembled using a second hand among the plurality of hands and a secondoperation base, which is an operation base other than the firstoperation base, after the first operation step, wherein the secondoperation base is raised, during a period between a start of the firstoperation step and a start of the second operation step, to a height atwhich the plurality of hands and the second operation base do notinterfere with each other.
 10. The automated assembly method accordingto claim 9, wherein the assembly robot does not have a driving unit in aZ-axis direction.
 11. The automated assembly method according to claim9, wherein the first operation step and/or the second operation step isperformed while detecting a distance in the Z-axis direction between ahand among the plurality of hands and an operation base among theplurality of operation bases.
 12. The automated assembly apparatusaccording to claim 1, wherein the control unit raises a first operationbase among the plurality of operation bases in the vertical direction bythe respective Z-axis moving unit to a position at which the firstoperation base does not interfere with a first one of the plurality ofhands, before the assembly robot reaches a position in which the firstone of the plurality of hands is positioned above the first operationbase, and raises a second operation base among the plurality ofoperation bases in the vertical direction by the respective Z-axismoving unit to a position at which the second operation base does notinterfere with a second one of the plurality of hands, before theassembly robot reaches a position in which the second one of theplurality of hands is positioned above the second operation base.